Active Adaptive Gyrostabiliser Control System

A gyrostabiliser control system and method for stabilising marine vessel motion based on precession information only. The control system employs an Automatic Gain Control (AGC) precession controller (60). This system operates with a gain factor that is always being gradually minimized so as to let the gyro flywheel (12) develop as much precession as possible - the higher the precession, the higher the roll stabilising moment. This continuous gain change provides adaptation to changes in sea state and sailing conditions. The system effectively predicts the likelihood of maximum precession being reached. Should this event be detected, then the gain is rapidly increased so as to provide a breaking precession torque. Once the event has passed, the system again attempts to gradually decrease the gain.

Comparison of active-set method deconvolution and matched-filtering for derivation of an ultrasound transit time spectrum

The quality of ultrasound computed tomography imaging is primarily determined by the accuracy of ultrasound transit time measurement. A major problem in analysis is the overlap of signals making it difficult to detect the correct transit time. The current standard is to apply a matched-filtering approach to the input and output signals. This study compares the matched-filtering technique with active set deconvolution to derive a transit time spectrum from a coded excitation chirp signal and the measured output signal. The ultrasound wave travels in a direct and a reflected path to the receiver, resulting in an overlap in the recorded output signal. The matched-filtering and deconvolution techniques were applied to determine the transit times associated with the two signal paths. Both techniques were able to detect the two different transit times; while matched-filtering has a better accuracy (0.13 μs vs. 0.18 μs standard deviation), deconvolution has a 3.5 times improved side-lobe to main-lobe ratio. A higher side-lobe suppression is important to further improve image fidelity. These results suggest that a future combination of both techniques would provide improved signal detection and hence improved image fidelity.

Pedagogical tools designed to promote engagement and active learning in the biomedical sciences and allied health disciplines

Perceiving students, science students especially, as mere consumers of facts and information belies the importance of a need to engage them with the principles underlying those facts and is counter-intuitive to the facilitation of knowledge and understanding. Traditional didactic lecture approaches need a re-think if student classroom engagement and active learning are to be valued over fact memorisation and fact recall. In our undergraduate biomedical science programs across Years 1, 2 and 3 in the Faculty of Health at QUT, we have developed an authentic learning model with an embedded suite of pedagogical strategies that foster classroom engagement and allow for active learning in the sub-discipline area of medical bacteriology. The suite of pedagogical tools we have developed have been designed to enable their translation, with appropriate fine-tuning, to most biomedical and allied health discipline teaching and learning contexts. Indeed, aspects of the pedagogy have been successfully translated to the nursing microbiology study stream at QUT. The aims underpinning the pedagogy are for our students to: (1) Connect scientific theory with scientific practice in a more direct and authentic way, (2) Construct factual knowledge and facilitate a deeper understanding, and (3) Develop and refine their higher order flexible thinking and problem solving skills, both semi-independently and independently. The mindset and role of the teaching staff is critical to this approach since for the strategy to be successful tertiary teachers need to abandon traditional instructional modalities based on one-way information delivery. Face-to-face classroom interactions between students and lecturer enable realisation of pedagogical aims (1), (2) and (3). The strategy we have adopted encourages teachers to view themselves more as expert guides in what is very much a student-focused process of scientific exploration and learning. Specific pedagogical strategies embedded in the authentic learning model we have developed include: (i) interactive lecture-tutorial hybrids or lectorials featuring teacher role-plays as well as class-level question-and-answer sessions, (ii) inclusion of “dry” laboratory activities during lectorials to prepare students for the wet laboratory to follow, (iii) real-world problem-solving exercises conducted during both lectorials and wet laboratory sessions, and (iv) designing class activities and formative assessments that probe a student’s higher order flexible thinking skills. Flexible thinking in this context encompasses analytical, critical, deductive, scientific and professional thinking modes. The strategic approach outlined above is designed to provide multiple opportunities for students to apply principles flexibly according to a given situation or context, to adapt methods of inquiry strategically, to go beyond mechanical application of formulaic approaches, and to as much as possible self-appraise their own thinking and problem solving. The pedagogical tools have been developed within both workplace (real world) and theoretical frameworks. The philosophical core of the pedagogy is a coherent pathway of teaching and learning which we, and many of our students, believe is more conducive to student engagement and active learning in the classroom. Qualitative and quantitative data derived from online and hardcopy evaluations, solicited and unsolicited student and graduate feedback, anecdotal evidence as well as peer review indicate that: (i) our students are engaging with the pedagogy, (ii) a constructivist, authentic-learning approach promotes active learning, and (iii) students are better prepared for workplace transition.

Empowering innovative and active citizens: Design education in an Australian independent school

Consumerism is arguably one of the strongest forces affecting society today. Its affect on young people and their ability and desire to create, design, and innovate is cause for concern. It has been suggested that design, when viewed as “a fundamental category of meaning making” (Cope and Kalantzis, 2010, p.597), can be conceived as a “foundational paradigm for representation and action” (Cope and Kalantzis, 2011, p.49). As a component of a general education, it has the capacity to give future generations a framework for collaborative creative and critical thinking required for business innovation, while developing resourceful optimism, motivation, morality and the citizenship needed to develop awareness and resilience to this ideology (Design Commission, 2011; Design Council, 2011). However, to date clearly defined frameworks and empirical data surrounding design education integration in secondary school contexts and its impact on innovation and active citizenship in Australia, is extremely limited. This paper will explore the value of a hands-on and collaborative design-based education model in an independent secondary school environment in Australia and its effect on students’ self- perception, core beliefs, empowered participation and ability to innovate towards sustainability. Following is an overview of relevant literature, the research question, and potential significance and contribution of this research.

Analyzing hysteresis behavior of capacitance-voltage characteristics of IZO/C₆₀/pentacene/Au diodes with a hole-transport electron-blocking polyterpenol layer by electric-field-induced optical second-harmonic generation measurement

By using electric-field-induced optical second-harmonic generation (EFISHG) measurement, we analyzed hysteresis behavior of capacitance-voltage (C-V) characteristics of IZO/polyterpenol (PT)/C₆₀/pentacene/Au diodes, where PT layer is actively working as a hole-transport electron-blocking layer. The EFISHG measurement verified the presence of interface accumulated charges in the diodes, and showed that a space charge electric field from accumulated excess electrons (holes) that remain at the PT/C₆₀ (C₆₀/pentacene) interface is responsible for the hysteresis loop observed in the C-V characteristics.

Investigation of interfacial charging and discharging in double-layer pentacene-based metal-insulator-metal device with polyterpenol blocking layer using electric field induced second harmonic generation

Time-resolved electric field induced second harmonic generation technique was used to probe the carrier transients within double-layer pentacene-based MIM devices. Polyterpenol thin films fabricated from non-synthetic environmentally sustainable source were used as a blocking layer to assist in visualisation of single-species carrier transportation during charging and discharging under different bias conditions. Results demonstrated that carrier transients were comprised of charging on electrodes, followed by carrier injection and charging of the interface. Polyterpenol was demonstrated to be a sound blocking material and can therefore be effectively used for probing of double-layer devices using EFISHG.

Fabrication and characterization of polyterpenol as an insulating layer and incorporated organic field effect transistor

A non-synthetic polymer material, polyterpenol, was fabricated using a dry polymerization process namely RF plasma polymerization from an environmentally friendly monomer and its surface, optical and electrical properties investigated. Polyterpenol films were found to be transparent over the visible wavelength range, with a smooth surface with an average roughness of less than 0.4 nm and hardness of 0.4 GPa. The dielectric constant of 3.4 for polyterpenol was higher than that of the conventional polymer materials used in the organic electronic devices. The non-synthetic polymer material was then implemented as a surface modification of the gate insulator in field effect transistor (OFET) and the properties of the device were examined. In comparison to the similar device without the polymer insulating layer, the polyterpenol based OFET device showed significant improvements. The addition of the polyterpenol interlayer in the OFET shifted the threshold voltage significantly; + 20 V to -3 V. The presence of trapped charge was not observed in the polyterpenol interlayer. This assisted in the improvement of effective mobility from 0.012 to 0.021 cm 2/Vs. The switching property of the polyterpenol based OFET was also improved; 107 compared to 104. The results showed that the non-synthetic polyterpenol polymer film is a promising candidate of insulators in electronic devices.

Post-deposition ageing reactions of plasma derived polyterpenol thin films

Owing to the structural flexibility, uncomplicated processing and manufacturing capabilities, plasma polymers are the subject of active academic as well as industrial research. Polymer thin films prepared from non-synthetic monomers combine desirable optical and physical properties with biocompatibility and environmental sustainability. However, the ultimate expediency and implementation of such materials will dependent on the stability of these properties under varied environmental conditions. Polyterpenol thin films were manufactured at different deposition powers. Under ambient conditions, the bulk of ageing occurred within first 150h after deposition and was attributed to oxidation and volumetric relaxation. Films observed for further 12 months showed no significant changes in thickness or refractive index. Thermal degradation behaviour indicated thermal stability increased for the films manufactured at higher RF powers. Annealing the films to 405°C resulted in full degradation, with retention between 0.29 and 0.99%, indicating films' potential as sacrificial material.

Novel modulation strategy for a CLC resonant dual active bridge

This paper proposes a novel modulation strategy for a phase controlled Capacitor-Inductor-Capacitor (CLC) Resonant Dual Active Bridge (RDAB). The proposed modulation strategy improves the soft turn-on, Zero-Current-Switching (ZCS) and Zero-Voltage-Switching (ZVS) range of the converter while only minimally increasing the required reactive currents in the ac link. A mathematical analysis of the proposed modulation scheme is presented along with a theoretical loss comparison between several modulation strategies. The proposed modulation strategy was implemented and the experimental results are presented.

Spray deposition of exfoliated MoS2 flakes as hole transport layer in perovskite-based photovoltaics

We propose the use of solution-processed molybdenum disulfide (MoS2) flakes as hole transport layer (HTL) for metal-organic perovskite solar cells. MoS2 bulk crystals are exfoliated in 2-propanol and deposited on perovskite layers by spray coating. We fabricated cells with glass/FTO/compact-TiO2/mesoporous-TiO2/CH3NH3PbI3/spiro- OMeTAD/Au structure and cells with the same structure but with MoS2 flakes as HTL instead of spiro-OMeTAD, the most widely used HTL. The electrical characterization of the cells with MoS2 as HTL show promising power conversion efficiency -η- of 3.9% with respect to cells with pristine spiro-OMeTAD (η=3.1%). Endurance test on 800-hour shelf life has shown higher stability for the MoS2–based cells (ΔPCE/PCE=-17%) with respect to the doped spiro-OMeTAD-based one (ΔPCE/PCE =-45%). Further improvements are expected with the optimization of the MoS2 deposition process

Combined effect of double antireflection coating and reversible molecular doping on performance of few-layer graphene/n-silicon Schottky barrier solar cells

Few-layer graphene films were grown by chemical vapor deposition and transferred onto n-type crystalline silicon wafers to fabricate graphene/n-silicon Schottky barrier solar cells. In order to increase the power conversion efficiency of such cells the graphene films were doped with nitric acid vapor and an antireflection treatment was implemented to reduce the sunlight reflection on the top of the device. The doping process increased the work function of the graphene film and had a beneficial effect on its conductivity. The deposition of a double antireflection coating led to an external quantum efficiency up to 90% across the visible and near infrared region, the highest ever reported for this type of devices. The combined effect of graphene doping and antireflection treatment allowed to reach a power conversion efficiency of 8.5% exceeding the pristine (undoped and uncoated) device performance by a factor of 4. The optical properties of the antireflection coating were found to be not affected by the exposure to nitric acid vapor and to remain stable over time.

A computer code for enclosed natural convection in the boundary layer regime

A computer code is developed for the numerical prediction of natural convection in rectangular two-dimensional cavities at high Rayleigh numbers. The governing equations are retained in the primitive variable form. The numerical method is based on finite differences and an ADI scheme. Convective terms may be approximated with either central or hybrid differencing for greater stability. A non-uniform grid distribution is possible for greater efficiency. The pressure is dealt with via a SIMPLE type algorithm and the use of a fast elliptic solver for the solenoidal velocity correction field significantly reduces computing times. Preliminary results indicate that the code is reasonably accurate, robust and fast compared with existing benchmarks and finite difference based codes, particularly at high Rayleigh numbers. Extension to three-dimensional problems and turbulence studies in similar geometries is readily possible and indicated.

The laminar boundary layer regime for natural convection of air in a square cavity

Numerical predictions are obtained for laminar natural convection of air in a square two dimensional cavity at high Rayleigh numbers. Proper resolution of the core reveals weak multi-cellular structure which varies in a complex manner as the effects of convection are increased. The end of the steady laminar regime is numerically estimated to occur at Ra=2.2x10^8.

Use of semi-active dampers in seismic mitigation of building structures

This research provides information for providing the required seismic mitigation in building structures through the use of semi active and passive dampers. The Magneto-Rheological (MR) semi-active damper model was developed using control algorithms and integrated into seismically excited structures as a time domain function. Linear and nonlinear structure models are evaluated in real time scenarios. Research information can be used for the design and construction of earthquake safe buildings with optimally employed MR dampers and MR-passive damper combinations.

Web-based active learning and frequent feedback: Engaging first-year university students

Web-based technology is particularly well-suited to promoting active student involvement in the processes of learning. All students enrolled in a first-year educational psychology unit were required to complete ten weekly online quizzes, ten weekly student-generated questions and ten weekly student answers to those questions. Results of an online survey of participating students strongly support the viability and perceived benefits of such an instructional approach. Although students reported that the 30 assessments were useful and reasonable, the most common theme to emerge from the professional reflections of participating lecturers was that the marking of questions and answers was unmanageable.